Water-scale formation in aqueous heat-exchange media is a formidable problem having adverse economic consequences since water-scale formed on the heat exchanger's walls impedes the heat exchange process. In an attempt to obviate this problem, various compounds have been suggested in the prior art as additives to aqueous heat exchange systems for the purpose of reducing the formation of water scale on the heat-exchange surfaces of these systems.
By way of illustration, U.S. Pat. No. 4,500,693 discloses a water-soluble co-polymer useful as a scale inhibitor and pigment dispersant. The co-polymer of this '693 patent comprises the product of the reaction of said at least one (mech)acrylic acid-based monomer with a select allyl ether-based monomer. This reaction is identified in the paragraph bridging columns 4 and 5. of the '693 patent as being typically conducted in an aqueous, organic or mixed aqueous/organic solvent medium.
As another illustration, Japanese Kokai No. 56/081320, published on July 3, 1981, discloses the reaction of polyethylene glycol-monoallyl ether with (meth)acrylic acid or a salt thereof to form a co-polymer said to be useful as a pigment dispersant and scale inhibitor. This Kokai discloses that the co-polymer is generally formed in an aqueous or organic solvent medium. In addition, Method 10 of the Kokai discloses a solvent-free reaction to produce a solid co-polymer. However, such a solid co-polymer is difficult to handle and thus impractical from a commercial processing standpoint.
In view of the large number of aqueous heat exchange systems employed in the chemical industry today, the development of new processes for making scale inhibitors is highly desired.